Pulse counting and registration system



Sept. 2, 1952 A. E. BACHELET ET AL 2,609,493

PULSE couunnc AND REGISTRATION SYSTEM Filed Jan. 7, 1950 2 SHEETS-SHEET 1 'Ar mRA/EY ep 1952 A. E. BACH ELET ETAL PULSE COUNTING AND REGISTRATION SYSTEM 2 Sl-iEETS-SHEET 2 Filed Jan. 7, 1950 4E BAGHELET IIVVENTORZ); LOW

626.8-wfl N St ATTORNEY Patented Sept. 2, 1952 UNITED STATES PATENT [OFFICE 2,609,498 H PULSE COUNTING AND REGISTRATION Albert E. Bachelet, New York, N. Y., and Frank K. Low, Orange, N. J assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application January 7, 1950, Serial No.'137,452

4 Claims. (c1. 250-277) This invention relates generally to signaling systems and more particularly to arrangements in such-systems for detecting and counting signal impulses.

The invention has for its main object to improve gas tube counting chains. In present-day signaling systems, such as may be used with automatic telephone systems, continuous improvement is being sought to increase the speed of response and the reliability of circuits used for detecting andcounting signals. In the telephone field in particular, continuous energy is expended towarddeveloping circuits which will respond more accurately andmore reliably at a rapid rate to signals, such as dial pulses or the like. An exemplary embodiment of the present invention is shown herein as incorporated in an automatic telephone system of the cross-bar type, such as disclosed in Patent 2,585,904 to A. J. Buschof February 19, 1952. A skeletonized disclosureof :the :Busch system is shown in another .copending application of J. W. Dehn, Serial No. 517,398 :filed. October '29, 1948. The Dehn disclosure shows some details of an originating register circuit of the cross-bar system whichcircuitfisshown herein modified to embed the .present invention. 1

The function of .anoriginating register, among others, in the -cross-bar system disclosed by Buschand Dehn,.is.to receive, detect, count, and register dial pulse digits transmitted thereto by a calling subscriber during the initiation by the latter .of a request for a connection. It is the improvement of such counting .circuits with which the present invention, in one of its forms, finds utility in improving the ,reliabilityof response ofsuch originating registersand in simplifyingsuch registers.

Briefly, the present invention contemplates a chain of gas-filledtubes for counting impulses andmeans .for applying all impulses to all tubes at'the sometime. Circuit means isprovided for interconnecting said tubes whereby a first im- Pulse will fire only the first tube and whereby the firing of any one tube conditions the other tubes vsuch that only the next succeeding tube fires on the "next pulse. Therefore, the firing of successive tubes in the chain corresponds to a succession of impulses in a series. Arrangement is made to recycle the chain at the end of a series of impulsessuch thatthe chain will count the next series as before for the first series. A check circuit is provided for detecting the failure of .any tube to fire when it is supposed to fire in response to an impulse. This check circuit feature is disclosed and claimed in Patent 2,597,428-to Albert E. Bachelet of May 20, 1952, which patent was allowed from an application which was a division of the present parent application.

The countingehain circuit improvement embodies one aspect'o'f the invention which characterizes the present invention over the prior art and such circuit is a variety of the type of counting circuit disclosed and claimed in a copending application of JL W. Dehn, Serial No. 136,008, filed December 30, 1949 and entitled Pulse Counting and Registration System. The checking means shown anddescribed in connection with the improved counting chain comprises a gas tube arrangement, the starter electrode circuit of which is energized by each-pulse which is applied to the counting tube chain. A delay means is interposed in the starter electrode circuit of the checking tube such that the impulse is not efiective to fire that tube until after a measurable delay time. The circuit arrangement is such that if at theduration of this delay time no counting tube has been fired, the checking tube will fire to indicate trouble. If, however, a counting-tube has fired, the checking'tube will be prevented from'firing. Other'featuresparticularly pointed-out in appended claims, will be apparent from the subsequent detailed exemplary embodiment of the invention, the drawings of the' disclosure being described generally as follows:-

Figs. land 2 combined show'parts of a crossbar originating register embodying the present invention;

Fig. 1 shows the pulse detecting and-counting circuit embodyingthe invention; and,

Fig.2 shows circuit means for registering the digits counted.

General description The present invention is herein disclosed as embodied in an automatic telephone system such as is' disclosed in the Patent 2,585,904 to A. J. Busch of February 19, 1952. Busch discloses in detail a cross-bar system wherein originating register circuits are used for transmitting-dial Another copending application of J. W. Dehn, Serial No. 57,398, filed October 29, 1948 discloses a skeletonized arrangement of the Busch disclosure including an originating register circuit in some detail. The Dehn and Busch disclosures may be referred to for details omitted from the present description as unnecessary for a complete understanding of the present invention.

The register relay arrangement shown in Fig. 2 is a variety of relay circuit arrangement disclosed and claimed in a copending application of F. K. Low, Serial No. 137,323, filed January 7, 1950, and entitled Pulse Counting and Registration Circuit.

As may be obtained from the Busch r Dehn disclosure, the general sequence of events during the originating of a call bya subscriber is as follows:

(1) The calling subscriber lifts his receiver thereby seizing an idle marker circuit and automatically informing the seized marker that a dial tone connection is desired;

(2) The seized marker tests for and seizes an idle originating register circuit;

(3) The marker interconnects the calling line with the seized originating register circuit over the cross-bar switch train and then the marker releases;

(4) The originating register transmits dial tone to the calling subscriber;

(5) The calling subscriber dials the digits of the called number or other desired destination;

(6) The originating register receives, follows, and counts the pulses of each digit and registers such digit; 7

(7) When sufficient digits have been registered therein the originating register seizes an idle marker circuit and transfers thereto, among other items of information pertaining to the call, the digits so registered; and,

(8) The marker, when it has received all of the information from the originating register, releases the originating register, completes the call, and then releases itself.

Since the present invention is embodied only in circuits of an originating register, in'so far as the present disclosure is concerned, the subsequent description will not cover items I, I, and 8 above. Such matters are fully dealt with by Busch and Dehn and are not necessary to the present description.

Each element of the present disclosure is referred to in the specification by a reference numeral or letter. Whenever, in the present disclosure, :3. reference letter is used it corresponds to the same reference letter as the drawing; but, for the convenience of the reader each such letter is followed in the description by a parenthetic number which designates the drawing figure upon which such referenced part appears. For instance, relay L(l) means the relay L on Fig. 1, etc.

Detailed description seizure of originating register Whenthemarker seizes an idle originating register circuit such as is disclosed partly in Figs. 1 and 2, the ofi-normal relay ON(l) thereof is operated by the marker.

Relay ON (1), upon operating, partly prepares the originating register-circuit for operation as follows:'

(1) Ground is applied over contact 6 of relay ON(l), contact 5 of relay'RPZQ) when relay RP2(l) is operated, to the armatures of relay RRAQ) associated with contacts 9 and I0 of that relay and, when relay RRAQ) is operated, extending over conductors I00 and IOI to Fig. 2 for purposes to be described hereinafter;

(2) Ground is applied over contact 5 of relay ON(l) contact 2 of relay RA5(1) to negative battery through the winding of relay B5(l), whereupon relay B5(l) operates;

(3) Ground is applied over contact 5 of relay ON(l) to the lower winding of relay RP2(1) for the purposes of locking relay RPZ (1) operated, as will be described hereinafter;

(4) Ground is applied over contact 3 of relay ON(l), conductor I02, contact I of relay I-IS(2), contact I of relay (2), to negative battery through the winding of relay AS(2), whereupon relay AS(2) operates:

(5) Ground is applied over contact 2 of relay ON(l), through resistance I03, to condenser I04 of the pulse forming network I23, comprising windings I05 and I06 and an asymmetrical resistance, such as dry rectifier I08, connected between negative battery and the upper armature of relay SR(l) (6) Positive battery is connected over contact I of relay ON(l) to the Off-normal battery conductor I09; and,

(7) Ground is connected over contact 4 of relay ON(l) to conductor H0 and thence in parallel through resistances 200, MI, 202, 204, and 20'! for the A digit register relays AO(2), AI (2) A2 (2) A4(2) and A1 (2) and through resistances 2I0 through 2II for the B digit relays BO(2) to 31(2), and likewise through resistances 210 to 217 for the H register relays HO(2) to H'I(2) and through the winding of each such relay to negative battery.

In regard to item (7) above, each of the register relays of Fig. 2, such as relay AO(2), will conduct a current limited by the resistance in series therewith, such as resistance 200. This amountof current will be referred to hereinafter as the holding current, which is insuiiicient to operate a relay but is sufiicient to hold a relay operated once it has been operated by an additional amount of current. Since these register relays of Fig. 2 utilize only front or make contacts a preferred embodiment thereof may be the magnetic reed type of relay such as is disclosed in the Patent 2,289,830 to W. B. Ellwood of July 14, 1942.

In regard to item (5) above, when ground is applied over contact 2 of relay ON(l) and through resistance I03 to the right-hand side of condenser I04, the left-hand side of condenser I04 is driven temporarily to substantially ground potential. At this instant the dry rectifier I08 represents a high impedance to this pulse. These rectifiers, such as rectifier I08, are arranged such that when the arrow side thereof is positive with respect to the other side of the rectifier, said rectifier will represent a low impedance, and when the reverse polarity situation occurs, said rectifier will represent a high impedance. Under the assumed condition, at which time ground appears on the left-hand side of condenser I04, rectifier {08 represents a high impedance for this pulse. Condenser I04 will charge very quickly in a circuit including negative battery, through the winding I06, through condenser I04 and resistance I03, to ground over contact 2 of relay ON(l). The fairly large charging current for condenser I04 passing through the coil I06 induces in the other coil I05 a total voltage with referfin e n gative battery of approximately 100 volts; positive, which appears. on; the upper armature of relay SR(1). Since relay-SE05)- is: notv operated; at: this; time this, IOU-volt positive pulse is. ineffective; The; left-hand side-.of:c=on.- denser Hi4. returns; to substantially negative bat-- tery potential. as soon. as; condenser I 04. becomes fully charged. Therefore, on the uppenarmatureof relay SR I there,- Will appear: a short pulse. of; approximately 1G0:--volt; amplitude in. a: positive; direction with respectzto negative battery.

In regard to: item 6.): above; positive battery is: applied. over; contact. I. of; relay ON;(1'). to: the: ofi-normal battery. conductor: Hi9, throughcom denser I ill, to. the starterelectrode. of tube; ST.( 1 since the cathode of'tube ST(1'). is at negative; battery potential through resistance. I90; tube. STU) will fire and. the. discharge will transfer: to. a circuit extending from. negative: battery, through resistance: I98; to the cathode of; tube. SIKl') across the: main gap. discharge path. of' tube ST(1):, through resistance. l I i-and through: impedances l I2-- and M3, topositive battery on conductor M39. The: presence. of. condenser H4 connected to the cathode or tube STU) will effectively hold the cathode of tube 51 (1) at negative batterypot'ential during the initial transient period. Eventually, condenser l M'- will become charged to a potential on the cathode of tube ST(1) which is approximately'lOfi volts positive with respect to negative'battery.

Interconnection. between cailinc subscriber and originating register.

After the seizure bya marker. oianidl e originating register circuit as above. outlined,v the marker effects an interconnection over. the crossbar switch. train betweenthe seized register and the calling line. thereby closing the. ring. andv tip conductors H9. and I26 of'the register over the, calling line loop. Relay L(1) is operatedin a circuit extending from ground. through the upper left secondarywinding of the dial tone transformer I2I,,conductorj I2i3, over. the switch train and the. line. loop, back over conductor I I9, through the lower left se.cond'ary winding of the dial tone transformer I121, andthroughthe wind-.- ing of. relay L(1). to. negative. battery... Relay L(l), upon operating, operates. relay. SRil). in. an obvious circuit over. contact I of, relay L(1).

Relay SR.(1)., upon operatingcloses. at its con tacti a circuit from the pulse network or pulse transformer I23 tothe.pulsingconductor. 22. for a purpose. to be. described-hereinafter.

The structure of. the relay L(l). is. preferably,

but notnecessarily, or the. mercury contact type t similar to the structure of. the mercury contact relay disclosed in Patent 2,577,602 of December 4,. 195.1 to- E- T.. Burton. The armatures, or armature, of relay. L(l.). arebiased towardsthe contacts 2, and d. This bias, asinthe. type of relay disclosed by Burton, maybe both partly mechanical due. to the usual spring and partly magnetic due. to. the, presence of. a, permanent. magnet, if. desired, influencing contacts. 2 and. 4. When relay L( 1 is. operated, under closed. loopv conditions, the current flow through. the right winding is arranged to. counteract partly the. effect of the, current. flowing. through. the. left winding. This, in effect, increases the. totalbias. tending to release the armatures when. relay L(l) is operated. This is to improve the releasing response of relay L(l), thereby aiding" its performance under line conditions which tend t'o'retard'the release of relay L(1). The purpose of the middle winding in series with condenser 2 RAM) thereby extinguishing tube- RA-( lay RRAG), upon operating, accomplishes no a potential.- of; negative; battery. Upon. the operation of relayLflI); condenser I I 6. will begin to acquire-a. charge positive. with respect: to negativetbatt'ery in a.-,circuit1extending from positive battery' over contact I. of relay ON(1'). through resistance I24, through the winding off relay RRAtDJ, through. resistance- I26; and. through condenser Hi6 to. ground:. Condenser H6. willthereupon. beginto'acquirea .positive charge with reference. to. the: negative. charge that it previously hadacquired'. Ifs're'lay I;( 1) remains op-- erated for asuflibientlength of time, condenser US will, during: thattime, acquire a sufficient charge of positive potentialiwith respect tonegative battery'on the cathode of tubeuRi'HI) to cause: an ionization across: the" starter electrode gap from: cathode oftubevRAtl): to the starter electrode I-ITI of tube- RA (I Assuming: forthepresent' that" the calling-subscriber' delaysbeforei dialing the additional digit for a sufficienttime-td permit condenser II'6 to acquire such a charge, tube RA-(-1) will fire, thereby causin a discharge across the-main gap in a circuit extending fromnegative battery to thecathode-of the-=tube=R-A(1)' across the main discharge path oftubeH-Atll to-the main anode H8, through the winding of relay BRA-(l) through condenser I25 (which, under the transient condition, represents"substantially a short circuit across resistance I 2-4) to oil-normal positive battery on conductor- IBB Relay BRA-(1) will operate in this circuit, looking over itscontact 6 to negative batteryover contact 3 of relay 11(1). This negative locking battery for relay RRAG) extends back to the main anode of tube useful function at this time. The operation of relay RRAQ), as' withthe discharge through tube RAM), is for the-purpose of timing the interdigi'tal' pause forextendin'gthe pulse count to the registers of Fig: 2, as will Ice-explained hereinafter.

Upon the first release of relay L(1') responsive to the first openline period of the firstpulse,

, layRRACl) will be released and condenser I I6 will be fully discharged over contact 4 of relay 1161').

Dial toneis transmitted from the source lZl thereof, through transformer I2I',.to'the calling subscriber who may'then' begin to dial; the called number; It will be assumed. that the calling subscriber begins-to dial the initial digit; before condenser IIS can acquire sufficient' charge to fire tube RACI'), as'ab'ove described.

Counting initial digit of" one" An" initial 1 digit of one pulse, unless followed directlyby a second. digit of one pulse asrwill be explained, is assumed. not to be. alegitimatesignal, because. of. the frequency with which such erroneous, indication may. be. effected by 2,001?" dental manipulation of the. subscribers dial, by spurious electrical'limpul'ses; etc. Suchan initial digit is' absorbed on the basis of the. above. assumption; but, as will be explained, it is not dis- 7. carded in view of the fact that a second digit of one pulse is presumed to indicate a legitimate I I prefix for a toll directing code or special service code of IIX, Where X maybe any digit from 2 to 9.

When relay L(1) releases, in response to the first open loop period of the first pulse of the first digit, condenser H6 in the starter electrode circuit of tube RAG) will be discharged as previously described over contact 4 of relay M1), and relay RRAG) will be released if it had previously been operated. Relay SRQ), due to its slow-releasing characteristic, will remain operated during the release periods of relay L(l) representing pulses of digits.

Upon the first release of relay Lil), negative battery is applied over contact 2 of relay Lil), contact 2 of relay SR(1) to condenser I04. Since at this time the left-hand side of condenser I04 is held substantially at negative battery, the application to the right-hand side of condenser I04 of negative battery will drive the left-hand side of condenser I04 to a potential which will be approximately negative battery plus negative battery; that is, assuming that negative battery is -48 volts, if 48 volts is applied to the righthand side of condenser I04, the left-hand side thereof will be driven temporarily to approximate 96 volts. It will be observed that under these conditions the upper or arrow side of rectifier I08 will be substantially 48 volts more positive than the lower plate of rectifier I08.

Under these conditions rectifier I08 represents a of relay SR(1) is substantially at negative battery potential and consequently condenser I25, in the starter electrode circuit of tube CK(1), will have acquired a charge of substantially negative battery in the circuit including resistor I28, contact I of relay SR(1), to negative battery through the windings of transformer I23.

Upon the reoperation of relay 14(1), at the end of the first pulse of the first digit, condenser H6 in the starter electrode circuit of tube RAG) is permitted to begin to acquire a charge, as above described, for measuring the interdigital pause. Relay L(1), uponreoperating, reenergizes relay SRU) and removes at contact 2 of relay L(1) negative battery from the right side of condenser 504. Ground will again be applied over contact 2 of relay ON(l) to the right-hand side of condenser I04 thereby, during the transient period, driving the left-hand side of condenser I04 to substantially ground potential. Under these circumstances it will be appreciated that varistor or dry rectifier I08 will have a voltage condition thereon whereby the upper or arrow side cfthe rectifier will be some 48 volts negative with respect to the lower plate thereof. Under these circumstances rectifier I08 will represent a high impedance and charging current for condenser H34 will be permitted to flow through the winding I66 of transformer I23. As a result of the flow of this current through winding I06, approximately 3, 100-volt pulse'is produced at contact of relay SR(1) by autotransformer action.

through the coil I05 of transformer I 23. This positive pulse of approximate 100 volts with re-- to the positive pulse on conductor I22.

spect to negative battery appears on the pulsing conductor I22.

It will be observed that the pulsing conductor I22 is connected in parallel to the starter electrode circuits of all of the tubes PI(1), P2(1), P3(l), P4(l), P5(l) and A5(l) through respective resistances I3I, I32, I33, I34, I35 and I36 and through respective condensers IBI, I62, I63, I64, I65 and I66. It will also be observed that the cathodes of tubes PI(1), P3(l), P4(1) and P5(l) are connected to negative battery through respective resistances I5I, I53, I54 and I55 and that the cathode of tube P2(1) is connected to negative battery through the upper winding of relay RP2 (1) and over contact 3 of relay RP2(1). Each of the tubes P2(l), 1 3(1), P4(1), P5(l) and A5(l) has associated therewith a rectifier I42, I43, I44, I and I46 connected between the starter electrode circuit of the associated tube and the cathode of the previous tube, such as rectifier I46 for tube A5(1) connected between the junction of resistance I36 and condenser I66 to the cathode of tube P5(l). Rectifier I4I, associated with tube PI(1), is connected to the cathode of tube ST(1) through an additional rectifier 130 having in parallel therewith a condenser I for a purpose to be described hereinafter. Rectifier I4I associated with tube PI(1) is also connected to negative battery through an additional rectifier I40 and resistance I in the cathode circuit of tube P5(l).

The above-described rectifier circuit arrangements, associated with the various tubes of the counting chain, are arranged such that at this time tube PI (1) isthe only tube which can fire in response to the first positive pulse on pulsing conductor I22. Since tube STU) is the only tube which is conducting at this moment the cathodes of tubes PICl), P2(1), P3(1), P4(l) and P5(l) will all be held at substantially negative battery potential. Since the positive pulse on conductor I22 is approximately volts positive with respect to negative battery, it is obvious that for all parts of this positive pulse the rectifiers connected to the cathodes of tubes PIG) through P5(l) represent substantially a low impedance shunt to said pulses. Therefore, none of the tubes 1 2(1) through A5(l) can fire in response to the first positive pulse on conductor I22.

Since tube STU) is conducting, its cathode, due to the voltage'drop across resistance I90, will be maintained at approximately 100 volts positive with respect to negative battery. Therefore, rectifier I30 will represent a low impedance to the positive pulse on conductor I22. At the same time, the right-hand or arrow side of rectifier I40 is held substantially at negative battery potential on the cathode of tube P5(l) thereby making rectifier I40 a high impedance with respect Under these circumstances the rectifier I5! connected to the starter electrode circuit of tube PI (1) will represent a high impedance to the positive pulse on conductor I22 thereby ionizing the starter gap of tube PI(1) and permitting a discharge therethrough in a circuit extending from negative battery through resistance I5I, cathode of tube PI(1) to the main anode of tube PI (1), through the common anode load for all the pulse tubes consisting of resistance III and impedances H2 and H3 to positive off-normal battery on conductor I09.

When tube PI(1) fires, as above described in response to the first positive pulse on the pulsing conductor I22, it causes an additional voltage acetate drop in the common anode load including resistance III for all of the pulse counting tubes thereby reducing the main-anode voltage on tube ST(1) to such a value that tube ST(1') extinguishes. When tube 'ST(1) extinguishes it cannot refi-re due to the following'two'considerations:

(l) The cathode of "tube STU) is held tem- Dorarily at substantially IOU-volt positive potential with respect to negative battery by reason of the presence of condenser I I4; and, v

(2) condenser IDI 'inthe starter electrode circuitof tube ST( l) hason the right s'idethere'of a charge of substantially negative battery potential.

Eventually the positive charge 'on condenser H4 will be discharged through resistance I90 thereby raising the cathode of tube S'Ifl) to substantially negative battery potential to, in effect, make rectifier I30 appear as a 'highfimp'edance to positive pulses on conductor I22. When tube PI 1) fired, as above described thereby reducing the available main anode voltage for tube -ST'('1) to extinguish the latter, the condenser I52 con nected to the cathode of tube PI(1) maintains substantially negative battery potential temporarily on the cathode of tube PHI) such that the drop in the main anodevoltage will not be sufiicient to prevent tube Pl-(l') from firing. Eventually, condenser, I52 charges up to subst'anl tia-lly 100 volts positive with respect to negative battery due to the '-disc'harge current flowing through resistance I5I in the'c'athode circuit of tube PI(1). The approximatelyv -100=volt rise in the positive direction of the potential of the cathode of tube PIKl) will be recognized, in View of previous discussion, as reversingthe polarity of voltage across rectifier I42 thereby, in effect, causing rectifier I42 to appear as .a high imped ance to any subsequent positive pulse on conductor I22. This, in efiect, conditions'tubeP211) to fire on the next pulse. 7 v I Under the conditions when tubes '"ST('1) and 1 5(1) are both not conducting, as is the condition for the next pulses on conductor I22, it'wi ll be appreciated that rectifiers I IU' and I30both represent-a high impedance to a positive pulse which may occur on the pulsing conductor I22. For-the cases where itis' desired that the next pulse on 'conductor I22 willffire' tube l =!3(1),, or PAH) or P5 (1'), it is not desired thatjthis pulse also beefiective to fire tubePHl). For those cases condenser I50; .which'i's in shunt of 're'ctp fier H30, is efiective under the transient condi--- tions concurrent with the sharp positive pulse on the pulsing conductor I22, to represent substantially a short circuit 'around'the rectifier I30 therebyin effect placing the bottom side or rectiiier MI at substantially negative battery .potential from the cathode of tube ST(1 making rectifier IM substantially a, low impedance shunt for these pulses on conductor I22.

As has been mentioned previously; upon the time constant of this charging circuit is such that if the reoperation of relay L(l) lasts for a short interval of time representing merely a pause between pulses of a digit, then. condenser H6 will not acquire suflicient charg ib'ylthe time relay 11(1) again releases to discharge condenser H6 to fire tube 'Rifi l'); but, if the reoperation of relay L'(1-) lasts for a relatively long interval of time r'epresentingan interdigital pause, then condenser IIIi will acquire'suflicient charge, beforerelay L(l') again releases to fire tube RA('1) has been-assumed, the first pulse is considered to represent a one-pulse digit; Relay L'("1) will remain operated long enough to permit the condenser ;I I6 -t'o;acquire a charge sufficient to fire tube RAG). When tube R'Afil') fires, as has been previously described, the main discharge occurs in acircuit extending from negative battery across the main discharge gap of tube RAG), through the winding of relay 'RRAU), throughcondenser I 25 to'positive battery on conductor Hi9, Relay RRA(1)"operates this dischargepath and locks'over it's'c'ontactt to ne'ga' ti've battery over contact Sfof relay L(1). This negative locking b'atteryds 'extendediback to the main anode II8 of tube RAQ'), thereby extinguishing tube RA(1) and "discharging condenser 'IIG.

Relay RRAQ) upon operating, extendsa circuit from 'the'cathode of each of'the tubes 125(1), P4;(1),'P3(1 and P2(l) oyer respective, contacts I, 2, 3 and 4 of relay RRn ('1).,t'o respective pairs of rectifiers I3'I-I38, 139441, I48I49 and extended over contact 5 of re1ay RRA(1) j contact I of relay RP.2(1 'topondenser lsuassoa ciated with tubes 'IIA(1) and IIB,(1). If relay RP2(1 were operated, "under conditions to be described hereinafter, the connection fromfthe cathode of tube PI.(1 would be, extended over contact 2 of -relayRP2 (1-)' to the pair of rectifiers I58*I59. I f Conductors 17 t, Iii, I72, I74 and l 'il'extend overrespective contacts 5, 4, 3,}2and I of relay AS-(2) to the left-hand sides of the windings of respective A digit register relays AIJ (2'), AI(2), A2'(2), A4'(2) and A I(2). Twoout ofthe'se five ccntrductors are to be jenergized'by positive battery thereon, on atw'o-out-of-five code basis, for operating two of "th'ejfiveA digit register "reiaysfbr Fig. '2 in accordance withthelfol lbvvlihg od'i Conductors Energized Gonduc'tors u Energized. Digit 1 The cathode circuits of all tubes-, which are extended by the peration of ,relayRRA-(l to the pairs of rectifiers abovedescribeisare all at substantially negative battery potential, thereby in eifect making the topfour pairs of rectifiers high impedances. The bottom .two rectifiers i58-I59 have no potential on their arrow sides due to the factithat relayRPZIl) is notopera ted at this time. Thus, noneofthe Adigit register relays of Fig. 2 will be. operated in response to the counting of the initialflone-ipulse digit, and such initial one-pulse-digit is .absorbed'in a manner to be described shortly. i

Due tothe fact thatrelay RP2 (1) is not-operated, the positive voltage of substantially lOO volt value with respect "to negative battery on'the cathode o-ftube PI (1) is extended over contact 5 of relay RRA(1) ,-'contact I of. relay RP2(1), to the condenser I60 as previously "described. Before relay'RRAt-l) operated,- condenser- Was charged to negative battery potential on its 11 right side in a circuit extending from ground through resistance I16, through condenser I60, and through resistance I to negative battery. When the positive voltage of approximately 100 volts positive with respect to-negative battery is extended from the cathode of tube PI(1) to the right side of condenser I60, this positive voltage drives the left-hand side of condenser I60 temporarily to a voltage of approximately 100 volts positive with respect to negative battery. At this point the polarity of rectifier IE7 is such as to represent a high impedance to this pulse. This positive voltage will quickly charge condenser I60 to the positive voltage value whereupon the lefthand side of condenser I60 will rapidly rise to about 100 volts and then return again to substantially ground potential. This positive pulseon the left-hand side of condenser I66 is applied through resistance I69 and condenser II8 to the starter electrode of tube I IA( 1), whereupon tube I IA(1) fires and a discharge occurs from ground through condenser I8I, cathode of tube IIA(1), across the main anode discharge path of tube IIA(1), through the anode load resistance I85 to positive battery on the off-normal conductor I09. Since the cathode of tube IIA(1) is held temporarily at substantially negative battery potential by the presenceof condenser I8I, the rectifier I79 connected to the cathode of tube IIA(I) will represent a lowimpedance shunt to the positive pulse as far as the starter electrode circuit of tube I IB(l) is concerned. Tube I IB(1) therefore will not fire on this first positive impulse.

Relay RRAQ) upon operating extends, over its contact 8, positive battery on conductor I09 to the junction between resistances I86 and I81 associated with the starter electrode circuit of tube ST(1). This positive voltage discharges condenser IIII, driving the starter electrode of tube ST(1) sufficiently in the positive direction to ionize tube STU) whereupon tube ST (1) discharges in a circuit including ground through condenser II4, cathode of tube -ST(l), across the main anode discharge path of tube ST(1) to the main anode of tube STU), through the anode load I I I common to all counting tubes, to positive battery on conductor I09. Since the main anode of tube PI (1) is supplied by positive battery through the same common anode resistor I I I, as was the main anode of tube ST(1), the reduction of main anode voltage due to the additional discharge through tube ST(1) will reduce the main anode voltage of tube PI (1) to such a value as will cause the extinguishing of tube PI 1) as has been previously explained. This reverts the starting chain to its initial condition preparatory to receiving, detecting, and counting the number of pulses in the second digit.

A second digit of one pulse If a second digit of one pulse is received and counted by the originating register circuit, it is assumed that this is a legitimate indicaton of a II prefix to a toll directing code or to a special IIX code of a service nature.

When relay L(l) releases in response to the first open line loop period pulse of the second digit, condenser H6 is discharged over contact 4 of relay L(l) and negative battery is applied over contact 2 of relay L(l), contact 2 of relay SR,(1), t0 the pulse transformer I23 which, as has been previously explained due to the presence of the rectifier I08, shunts or short-circuits this negative pulse such that it is not effective on the pulsing conductor I22. a p

When relay L(l) reoperates at the end of the first pulse of the second digit, condenser H6 is permitted to begin to acquire a charge to measure the interdigital timing, as has been previously explained; and the removal of negative battery from contact 2of relay L(l) causes the pulse transformer I23 to producea positive pulse on the pulsing conductor I22 as has been explained above. (Relay RRAG) was released when relay L(l) released during the first pulse of the second digit.) Thefirst pulse on pulsing conductor I22 fires tube PI(1) and the firing of tube Plil) extinguishes tube ST(1). Under the assumption thatthis second digit is also a one-pulse digit, condenser II6 will acquire sufiicient charge to fire tube RAG) thereby operating relay RRAQ) which relay locks under the control of the operated relay L(l), as previously explained, extinguishing tube RAM) and discharging condenser II6. Upon the operation of relay RRA(1) as above, the positive voltage on the cathode of tube PI(1) is extended over contact 5 of relay RRAQ), contact I of relay RP2(1) to the right-hand side of condenser I60 thereby producing on the left-hand side of condenser I60 the above-mentioned short positive pulse. By this time the condenser I8I in the cathode circuit of tubev IIA(1) has acquired a charge of substantially 100 volts positive with respect to negative battery at the cathode of tube I IA(1), thereby reversing the polarity across the rectifier I79 and making it appear as a high imp'edance to thenext positive pulse from condenser I66. This "second positive pulse through condenser I60 therefore willv be transmitted through resistance I68 to the starter electrode of tube IIB(1), firing tube IIB(1) in a discharge circuit extending from negative battery through the winding of relay I IX(1) ,resistance I63, across the cathode-main anode discharge circuit of tube IIB(1), through the anode load I85, common to tubes IIA(1) and 3(1), to positive battery on conductor I09. The additional drop in voltage through the resistance I85, 'due to theadditional firing of tube IIB(1) reduces the main anode voltage-0f tube IIA(l') 'to such an extent that tube IIA 1 extinguishe's. Relay IIX(1) operates inthe discharge circuit of tube 3(1) and locks over its contact, through resistance I84, to oilnormal positive b'atterylon' conductor I09. This positive locking battery, when extended to the cathode circuit of tube I'IB(1) over the contact of relay I IX(1), raisesthe cathode potential of tube IIB 1) to suchan extent as to extinguish tube IIB(1), byeffectively short-circuiting the main anode gap of tube IIB(1).

It will be appreciated that. any additional onepulse digits which maycome alonglaterwill be absorbed in the NAG) and IIB(1) tube circuits. It will be apparent, as has been previously expained, that no digit of the value of one pulse can be transmitted to the registers of Fig. 2 until relay RP2(1) operates, as will be explainedlater. It

' will also be appreciated that the operation of the Receipt of a digits value of at least-two pulses Let it be assumed that the next digit is of two or more pulses, say four. 7 When relay L(l) releases during the first pulse negative battery is appliedover contact 2 of relay L(1), contact 2 of relay SR(1), through condenser I 84, to the pulsing transformerI-23. When relay L'(1) reoperates the end of the first pulse, condenser H6 is permitted to start charging to measure the interdigital pause, and condenser I04 is again charged to create a positive pulse on the pulsing conductor I22. Since tube ST(l)'isconducting at this time, theflvaristor MI will effectively representa high impedance to the positive pulse on conductor I22 thereby causing tube PHI) to fire. Tube PI(1) in conducting extinguishes tube STU).

When relay L(1) releases during the second pulse, condenser I I6 is discharged and condenser IE4 is discharged. When relay L(1) reoperates at the end of the second pulse, condenser 'I I6 'begins to time the iinterdigital pause and'condenser I04 is again charged to create a positive pulse onconductor H2. The positive pulse on conductor I22 fires tube P2(l) because the rectifier I42 in the starter electrodecircuit of tube P'2(l) is eiiectively a high impedance because of the high positive voltage onthe cathode of the conducting tube PR1). Tube 1 2(1) conducts in a circuit extending from negative battery, contact3 .of relayRPZfl), upper winding of relay RP2(1),

cathode of tube .P2(1'), 'main anode discharge path of tube .PZtl), to positive voltage on conductor I89 through the common I'anode load resistance 'I It! and impedances II 2 and .I I3. Tube P2 (.1) in conducting extinguishes tube PI(1) by reducing the voltage at the main anode of tube PHI) to such an extentas to extinguish .tube Pl (1). Tube P.2(1) in' conducting in the abovetraced circuit, operates relay RP2(1). Relay 'RP2(1) locks .ina circuit from negative battery over contact e of relay RPZQ) through the lower winding of relay 'RP2.(1) to off-normal ground over contact 5 of relay ONQ).

In a similar manner, the third pulse fires tube P3 (1)- and extinguishesitube P2 (1) and the fourth pulse fires tube P4 (1), thereby extinguishing tube P3 (1). When relay L(1) reoperates at the end of the fourth pulse, condenser H6 will begin to the fourth pulse for a length ofatime sufiicientfor condenser I It to acquire sufiicientpositive charge to fire the tube RAG). When tube RA(1) fires, relay RRAQ) operates and looks as previously described, thereby extinguishing tube RAG) and discharging condenser H6. Upon the operation-of relay .RRAG), the high positive voltage existing at the cathode of tube P4(1) due to the fact that the latter tube is conducting, is extended over contact 2 ofrelay RRA(1) to the left-hand r arrow sides'of rectifiers I39 and I47. The right-hand sides of rectifiers I39 and I4? extend over'respective contacts 2 and 3 of relay 'B5( 1) to respective conductors I'll) and H4, over respective contacts and 2 of the A digit steering relay AS(2) to the left-hand sides of the windings of respective'rela'ys AO(2) and 134(2). Since the conduction of tube P4(1) makes the left or arrow side of rectifiers I 39 and I 41 of positive potential with respect to negative battery, these rectifiers will represent low Jimpedance in the'above-traced circuits, whereupon relays AO(2) and A4(2) will effectively have placed on the left-hand sides of their respective windingspositive battery. The resulting'increase -14 of current .through relays AO(2) :andAd (2) will produce a value of current sufficient to operate these two relays, whereupon relays AO(2) and A M 2) operate to register on a two-out-of-five basisthe first or A digit of the value of four pulses.

After the registration in the register relays AO(2) and A4 (2) of'the Adigit of four pulses, tube P4 (1) will be extinguished and relay RRAQ) will subsequently release upon the'release of relay L(1) during the first pulse of the .next succeeding digit. When tube P-I(l') is extinguished or when relay RRA(1) releases under these condi tions, positive battery is removed from the left side of respective windings of relays AO(2) and -A4'(2) thereby decreasing the current flowing "through these relays to :the original holding value. This value of current, as has been previously explained, however, is suificient to hold operated any relays of the digit register group which have been operated. Consequently, relays AO(2) and A4( 2) willremain operated under the control of off-normal groundon conductor Hi).

This arrangement of register relays wherein .no

denser I01 and fire tube ST'(1), thereby extinguishing tube P4(1) and reverting the pulse counting chain to its normalcounting condition. Furthermore, upon the operation of relay "RRAQ), ground is extended over contact'fi of relay ON( 1) contact 5 ofrelay RP2(1-), overcontacts "9 and I0 of relay RRAQ), conductors I00 and NH to the steering 'relay circuit'of Fig. 2. Ground on conductor Hi0 extends over contact 8 of relay AS(2) to hold-relay AS(2) operated when the holding circuit therefor is broken upon the operation of relay BS(2). Ground-on conductor I GI is extended over contact I0 of relay AS(2), to negative battery through the winding of the B digit; steering relay 38(2); Steering relay 138(2) operates in the circuit after the extinguishing of tube P4(1). its contact 6 and over contact 'I of relay HS (2) to off-normal-ground on'conductor I02. The operation ofthe B digit steering relay BS'(2) closes the five conductors IIILI'II, I72, I'M "and I'll over its respectivefcontacts 5, 4, 3, 2 and Ito the "B digit register relays (2) to 37(2) preparatory to registering the'second or B digits transmitted by the calling subscriber.

It will be observed that the ground circuitson conductors I00 and I 'O'I leading to Fig. 2 are not efiective until after relay R-P'(2) operates. This insures that no advance of the steering relays of Fig. 2 is permitted until at least one digit has been detected and counted which comprises two operated with relay B5(1) released whenever a.

digit is counted by the circuit of Fig. 1 as containing six or morepulses. The operation of one or theotherof'relays B5(1) or RA5(1) selectively extends the'Itw'o-out-of-five conductors from each of the five Ipa'irsof mariners-to various of the Relay-ESQ) locks over five conductors leading to the registers of Fig. 2, such that under one condition the conduction to any one of the tubes PI (1) through P(l) may represent either of two different digits depending upon whether the pulse count of a particular digit is below or above 5. For instance, with relay 35(1) operated, as in the above example,'the conduction of tube-PAH) indicates a pulse count of 4. However, if relay RAB (1) were operated instead of relay 35(1), then the conduction, of a tube such as P4(l) would extend positive battery over contact 2 of relay RRA(1) through rectifiers I39 and I41, over contacts 5 and 6 of relay RA5(1), to conductors I72 and I17, thereby indicating, on a. two-out-of-five basis, the digit 9. Therefore, in one case, tube P4(l) upon conducting indicates the digit 4 (below 5) and, in the other case, conduction of the tube P4(1) indicates the digit 9 (four pulses above 5).

Receipt oi B digit 4 Let it be assumed that the next digit is greater than or above 5, such as the digit 8. The counting tubes will progress as above described for-the first five pulses such that at the end of thefifth pulse the following conditions appear: a

(1) Relay L(1) has reoperated at the end of the fifth pulse;

(2) Tube P5(l) is conducting and all other tubes are extinguished; and, 1

(3) Relay RP2(1) is operated and locked.

Upon conduction through tube P5 (1) the oathode of tube P5(l) rises to substantially 100 volts positive potential with respect to negative battery, thereby conditioning varistor I46 such that the latter will represent a high impedance to the next pulse on conductor I22. The cathode of tube 1 5(1) also applies this high positive voltage to the right-hand or arrow side of rectifier I40 connected to rectifier MI in the starter electrode circuit of tube PHI). This-positive voltage on the right-hand side of rectifier I40 efiectively makes rectifier I423 a low impedance to positive pulses on conductor I 22, thereby in effect making rectifier I41 a high impedance to such pulses. Therefore, upon thenext pulse, that is, the sixth pulse on conductor I22, both tubes A5(1); and PI(1) willfire.

When relay -L(l) releases during the sixth pulse, condenser H6 is discharged, When relay LU) reoperates at the end of the sixth pulse, the pulsing conductor I22 will have applied thereto a high positive pulse from the. pulse transformer I23. This positive pulse on. conductor I22 will fire both tubes A5(l) and PI(1). Tube PI(1) upon conducting, extinguishes tube P5(1) since both of these tubes use the same common anode load resistance III and impedances H2 and H3, as has been explained previously. Tube A5(l) conducts in a circuit extending from negative battery, to cathode of tube A5(1), across the main anode conducting path tube A5 (l) through the winding of relay RA5(1), to positive battery on the off-normal conductor I09, thereby operating relay RA5(1). Relay RA5(l), upon operating, releases relay B5(l) by opening the operating circuit for the latter relay at contact 2 of relay RA5 (1) Tube A5(l) remains conducting and relay RA5(1) remains operated for successive pulses of the same digit.

In response to the seventh positive pulse on thepulsing conductor I22, tube P2( 1) fires, extinguishing tube PI (1). Furthermore, upon the eighth pulse on conductor I22, tube P3(l) .con-

ducts, thereby extinguishing tube P26.)

B digit register relays BI(2) and 131(2).

16 At the end of the eighth pulse, when relay L(1) reoperates, the latter will remain operated suificiently at this time to permit condenser IIB to fire tube RAG), thereby operating and looking relay RRAQ) as above, to in turn extinguish tube RA(1) and discharge condenser II6.

Relay 'RRA(1), upon operating, extends the positive potential on the cathode of tube P3(l),

over contact 3 of relay RRA(1) to the left-hand ill and IT! is extended'over respective contacts 4 and I of the 13 digit steering relay BS(2) to the left-hand sides of the windings of respective The current flowing through the windings of relays BI (2) and B'I(2) increases sufficiently to operate these two relays, thereby registering on a twoout-of five code basis the B digit 8 by the operation of-the B digit register relays BN2) and Relay RRAG) 'upon operating extends ground over its contact I, contact I of relay RA5(1), to

ground the main anode of tube A5(1), thereby extinguishing tube A5(1). Relay RRA(1), upon operating, also extends positive battery over its contact 8, to resistance I81 to discharge condenser I07 and refire tube STU), thereby extinguishing tube P3(1) to revert to the counting tube chain to its normal condition. Ground is extended from contact 6 of relay ON(1), over contact 5 of relay RP2(1), over contacts 9 and II! of relay RRAQ), over conductors I00 and IBI. Ground on conductor I00 extends over contact 9 of relay AS(2) and contact 8 of relay 138(2) to hold relay 138(2) operated when the locking circuit therefore is broken upon the operation of the next steering relay CS (not shown). Ground on conductor IUI is extended over contact II of relay AS(2), contact II! of relay 388(2), over conductor 203, to negative battery through the winding of the next steering relay CS (not shown) which operates and locks to off-normal ground on conductor I02 under the control of the next or DS steering relay (not shown).

When relay RRAG) is released, during the first pulse of the next digit, the previously'operated steering relay BS(2) releases leaving the subsequently operated steering relay CS (not shown) operated and locked under control of the fourth steering relay over off-normal ground on conductor I02 preparatory to operating on a two-out of-five basis the C digit register relay (not shown) of Fig. 2.

I Subsequent digits The receipt, detection, counting, steering and registering of subsequent digits are accomplished similarly to the above discussion and further detailed analysis of the circuit operation is considered unnecessary.

Checking circuit The checking tube CK( 1) with associated circuits, isprovided to indicate the failure of any tube ST(1) through A5(1) to ionize at a time when its respective ionization should occur.

It will be noted that the pulsing conductor I22 is connected to resistance I29 and through conaccents denser 128 to ;g1'O11l'1d -'Bt"'.th8 starter electrode circuit of tube TCK (1'). "Itxwill =also'be noted :that at any time-prior to'th'e productions-by transformer 1230f a positive pulse on the pulsinge'onductor I22, condenser I28 acquires a negative charge :in the circuit extending from ground, through con- :den'ser I,28,'through resistance I29, over contact I of relayv SEMI), to negative *batterythrough the windings I95 and I06 of the pulse-transformer I23. 'At such time as the pulse "transformer '=l23 produces a positive pulse, this positive pulse is applied to the starter electrode circuit .of tube CK(I). The negative charge on condenser I28 will be held there due to the presence of condenser I28 for a length o'i time depending upon the time constantof the circuit involving resistance -I29' and condenser I28. This means 'that'the positive pulse on the pulsing-conductor I 22 will notbemade effective to fire tube CKU') until ameasured interval of time 'after theapplication to that pulsing conductor I22 of the 'positive'pulse generated'by the pulse transformer I 23." At such time as the voltage-on condenser I28 shall'have risen to a positive value su'fiicient to fire tube CKU), ionization will occur across the starter electrode gap of that tube, which ionization will be manifested in a dischargeacross the main anode discharge gap 'of tube CK(-1') provided there is sufiicient main anode voltage at tube CK(1) to sustain the discharge. If there is suincient voltage at the main-anode of tube CK(1),'this dischargewill-occur in a circuit extending from negative battery through the winding of relayCKfl) ,-cathode" of tube CK( 1) ,main

anode of tube CKQ), through the anode load resistance III and 'impedances H2 and H3, to positive battery on conductor I09. It will be recalled that each of the tubes -ST(1-) through P5'(1') has its main anode connected "to positive battery through thesame common anode load resistance I II "and "impe'dances H2 and -I I3. I'heseload impedances and "resistance are arranged'such that if any of the tubes STU? through P5(1) fires andconducts a main discharge current, the voltage drop through these common anode impedances will be sufficient to reduce the main anode voltage of tube CK(1) 'sufiiciently such that tube CK(l) cannot sus-.,- tain a main gap discharge.

"It will be recalled that at thesame time that the starter electrode timing delay circuitof tube CK (1) was measuringan interval of time, the pulsing conductor I22 applied to the starterelectrodes of all of the countingtubes the high positive pulse. If that positive pulse fails to fire one 1 of the tubes .S'ILCI) through 'P5'('I) by the time that the condenser I28 in the starter electrode circuit of tube CK(1) fires tube CK(l), then a main discharge current will be sustained in tube CK(1) operating relay CK'(1) to indicate a signal of improper operation ofthe pulse counting circuit. On the other hand, if oneof the tubes ST(1) through P561) :doesfirein response to the positive impulse on the pulsing conductor I22, then the main anode, voltage of tube CK(1) will have .been reduced sufficiently .such that tube CKKI) cannot fire when the starter electrode thereof ionizes "the starter electrode-cathode gap of tube CK(1).

It will be appreciated then that the tubeCKflJ with "its associated circuit elements, is a checking means for determining the failure or noniailure of one of the tubes of the counting chain to fire in response to an impulse on the pulsing conductor I22.

r 18 Set-sing an iidlezmarkei'r 5 ,'When the originating register has registered, in .its relays of ,2, .suincientdigi'ts .to warrant seizure of anlidle marker circuit .for completion of the call, such .a marker may be seized under. the control, as disclosed. by Busch and. above, of the steering relays of .Fig. 2. .For instance, relay HS(2) will.operateafterthe seventh or G digit (exclusive of a II prefix) has been registered. Relay HS(2) may be arranged to complete the marker start circuit @after receipt and registrationof seven digits, which may. comprise a complete calling number of three .oflice codedigits and four numerical. a

Han-initial II prefix is;detected and-registered by the operation of relay I IX(l) relay .(2) may complete the marker start :circuit for :seiaing an idle marker {after .the 1X digit of :the :;I IX .code is registered in the A register of Fig; .2. .In this case the operated relay I I.X(-1) maybe arranged to transmit a special signal to "the seized marker.

Completion of connection I When anidle marker is seized, the information registered ,in the digit registers of .Fig. v2,along with other information, .is transferred to the marker on a two-out-of-five basis 'byground on two. out of five conductors from the contactso-f each group o'f-register relays.

The marker releases the originating register, thereby returning all apparatus of Figs. 1 and-2 to normal, completes the indicated connection. and releases leaving the connection under the vsupervisionof a trunk, for instance.

It is to be understood that the-above described arrangements are illustrative of .the (application .of the principles [of the invention. Numerous other arrangements may be devised by those skilled in the art Without departing from the .spirit and scope ;of the invention.

i. .In asignaling system. means :for generating signal impulses, :a chain :of gas-filledtubes for counting "said impulses, :said chain including a start tube and aplurality 1 of counting tubes', :means for applying said impulses simultaneously to all of said counting tubes, means for causing conduction" in said start tube prior to the generation .of aseries of impulses to be counted, gating means connected in circuit with each counting tube and being controlled by the next precedingtube of said chain, the gating means associated with only the'first counting tubebeing controlled also by the last counting tube of said -chain, each of said gating means being con trolled by a conducting tube to permit animpulse to cause conduction in the countin'g'tube associated with said means and next succeeding said conducting tube, each of said gating means except said means associated with the first counting tube "being controlled by a non-conducting tube to prevent an impulse from causing conduction in the-counting tube next succeeding'said non-conducting tube, and additional gating means to prevent an impulse from causinggconduction in the first counting tube whenever "the start tube and the last counting tube are both non-conducting.

2. In a signaling system, means for generating signal impulses, a chain of gas-filled tubes for counting said impulses, each tube comprising a cathode and a main anode and a starter electrode, said chain including a start tube and a plurality of counting tubes, means for applying said impulses simultaneously 'to the, starter electrode circuitsof allof said counting tubes, each tube having a separate cathode load and all'tubes having a common main anode load, means for causing conduction in said start tube prior to the generation of a series of impulses to be counted, an asymmetric impedance connected to the starter electrode circuit of each counting tube and being controlled by the oathode load of the next preceding tube of said chain, the said impedance associated with only the first counting tube being controlled also by the oathode load of the last counting tube of said chain, each of said impedances being controlled by the associated cathode load of a conducting tube to increase the shunt impedanceof said impedance to impulses thereby to permit an impulse to cause conduction in the counting tube associated with said impedance and next succeeding said conducting tube, each of said impedances except that associated with the first counting tube being controlled by the cathode load of a non-comducting tube to decrease the shunt impedance of said impedance to impulses thereby to prevent an impulse from causing conduction in the counting tube next succeeding said non-conducting tube, and circuit means associated with the starter electrode circuit of the first counting tube and with the cathode loads of the last counting tube and of said start tube to prevent an impulse from causing conduction in the first counting tube whenever the start tube and the last counting tube are both non-conducting.

3. In a signaling system, means for generating signal impulses, a chain of gas-filled tubes for counting said impulses, each tube comprising a cathode and a main anode and a starter electrode, said chain including a start tube and a plurality of counting tubes, means for applying said impulses simultaneously to the starter electrode circuits of all of said counting tubes, each tube having separate cathode load and having a' common main anode load, means for causing conduction in said start tube prior to the generation of the series of impulses to be counted, a separate dry rectifier connected from the starter electrode circuit of each counting tube except the first counting tube to the cathode of the next preceding counting tube, said rectifier being so poled that it represents low shunt impedance to said impulses thereby to prevent conduction in said counting tube in response to an impulse when said next preceding counting tube is not conducting and high shunt impedance to said impulses thereby to permit conduction in said counting tube in response to an impulse when said next preceding counting tube is conducting, a first dry rectifier connected to the starter electrode circuit of the first counting tube and poled in the same direction as said separate dry rectifiers, a second dry rectifier connected from said first rectifier to the cathode of said start tube and poled oppositely to said first rectifier, a third dry rectifier connected from said first rectifier to the cathode of said last counting tube and poled oppositely to said first rectifier, thereby to permit conduction in said first counting tube in response to an impulse when either said start tube or said last counting tube is conductinggand a condenser in shunt with said seconddry rectifier to prevent an impulse from causing conduction in said first counting tube whenever said start tube and said last counting tube are both non-conducting.

4. In a signaling system, means for generating positive signal impulses, a chain of gas-filled tubes for counting said impulses, each tube comprising a cathode and a main anode and a starter electrode, said chain including a start tube and a plurality of counting tubes, means for applying said impulses simultaneously to the starter electrode circuits of all of said counting tubes each tube having a separate cathode load and having a common'main anode load, means for causing conduction in said start tube prior to the generation of a series of impulses to be counted, a plurality of dry rectifiers each of which represents a low impedance when the positive terminal thereof is at a potential more positive than the negative potential thereof andeach representing a high impedance when the positive terminal thereof is at a potential less positive than the negative terminal thereof, a first rectifier havingits positive terminal con nected to the starter electrode circuit of each counting tube except the first counting tube and the negative terminal thereof connected to the cathode of the next preceding counting tube, whereby a said first rectifier represents low shunt impedance to said impulses thereby to prevent conduction in said counting tube in response to an impulse when said next preceding counting tube is not conducting and representing high shunt impedance to said impulses thereby to permit conduction in said counting tube in response to an impulse when said next preceding counting tube is conducting, a second rectifier having its positive terminal connected to the starter electrode circuit of the first counting tube, a third rectifier having its negative terminal connected to the negative terminal oi said second rectifier and having its positive terminal connected to the cathode of said start tube, a fourth rectifier having its negative terminal connected to the negative terminal of said second rectifier and having its positive terminal connected to the cathode of said last counting tube, thereby to permit conduction in said first counting tube in response to an impulse when either said start tube or said last counting tube is conducting, and a condenser in shunt with said third rectifier to prevent an impulse from causing conduction in said first counting tube whenever said start tube and said last counting tube are both non-conducting.

ALBERT E. BACI-IELET.

FRANK K. LQW.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Holden July 24, 1951 

